# -----------------------------------------------------------------------------
#  Copyright (C) 2019 Alberto Sottile
#
#  Distributed under the terms of the 3-clause BSD License.
# -----------------------------------------------------------------------------

import ctypes
import ctypes.util

appkit = ctypes.cdll.LoadLibrary(ctypes.util.find_library("AppKit"))
objc = ctypes.cdll.LoadLibrary(ctypes.util.find_library("objc"))

void_p = ctypes.c_void_p
ull = ctypes.c_uint64

objc.objc_getClass.restype = void_p
objc.sel_registerName.restype = void_p
objc.objc_msgSend.restype = void_p
objc.objc_msgSend.argtypes = [void_p, void_p]

msg = objc.objc_msgSend


def _utf8(s):
    if not isinstance(s, bytes):
        s = s.encode("utf8")
    return s


def n(name):
    return objc.sel_registerName(_utf8(name))


def C(classname):
    return objc.objc_getClass(_utf8(classname))


def theme():
    NSAutoreleasePool = objc.objc_getClass("NSAutoreleasePool")
    pool = msg(NSAutoreleasePool, n("alloc"))
    pool = msg(pool, n("init"))

    NSUserDefaults = C("NSUserDefaults")
    stdUserDef = msg(NSUserDefaults, n("standardUserDefaults"))

    NSString = C("NSString")

    key = msg(NSString, n("stringWithUTF8String:"), _utf8("AppleInterfaceStyle"))
    appearanceNS = msg(stdUserDef, n("stringForKey:"), void_p(key))
    appearanceC = msg(appearanceNS, n("UTF8String"))

    if appearanceC is not None:
        out = ctypes.string_at(appearanceC)
    else:
        out = None

    msg(pool, n("release"))

    if out is not None:
        return out.decode("utf-8")
    else:
        return "Light"


def isDark():
    return theme() == "Dark"


def isLight():
    return theme() == "Light"
